Repeat antivenom administration following crotalidae immune F(ab’)2 antivenom in Agkistrodon species: a case series

Figures & data

Table 1. Demographics and dosing regimens of 4 patients envenomated by an Agkistrodon contortrix requiring redosing after F(ab’)₂.

Patient	Age	Gender	Bite location	Initial antivenom dose	Subsequent antivenom dose	Comments
Case 1	13	Male	Right middle finger	10 vials F(ab’)2	4 vials Fab	Swelling progressed to elbow following F(ab’)2, control achieved after Fab.
Case 2	28	Male	Left index finger	10 vials F(ab’)2	Repeated 10 vials F(ab’)2	Swelling spread to left bicep after first dose of F(ab’)2, continued after second dose
Case 3	31	Male	Right index finger	10 vials F(ab’)2	Repeated 10 vials F(ab’)2, then given 6 vials Fab	Swelling progressed to bicep despite two boluses of F(ab’)2, stabilized following Fab.
Case 4	9	Female	Left index finger	10 vials F(ab’)2	4 vials Fab	Swelling progressed to elbow following F(ab’)2, control achieved after Fab.

Table 2. Laboratory parameters of included cases. Fibrinogen was a send out for the first hospital in case 4 and not obtained. AV = antivenom.

		At patient arrival	After first AV bolus	After second AV bolus	At discharge
Case 1	INR	1.01	Not repeated	1.1	Not repeated
	PLT (platelets per microliter)	269	238	248	Not repeated
	FIBRINOGEN (mg/dL)	230	Not repeated	227	Not repeated
Case 2	INR	1	0.95	0.95	Not repeated
	PLT (platelets per microliter)	236	223	223	Not repeated
	FIBRINOGEN (mg/dL)	417	372	372	Not repeated
Case 3	INR	0.9	1	0.9	0.9
	PLT (platelets per microliter)	375	335	329	306
	FIBRINOGEN (mg/dL)	268	271	322	334
Case 4	INR	1	1	1.1	Not repeated
	PLT (platelets per microliter)	219	180	177	Not repeated
	FIBRINOGEN (mg/dL)	Not obtained	203	239	Not repeated